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131.
Lin MJ Jouaiti A Grosshans P Kyritsakas N Hosseini MW 《Chemical communications (Cambridge, England)》2011,47(27):7635-7637
The combination of four enantiomerically pure organic tectons composed of a rigid chiral backbone bearing two terminal pyridyl coordinating sites with ZnSiF(6) behaving as an infinite pillar leads to the formation of tubular 2-D enantiomerically pure helical channels with controlled size and orientation. 相似文献
132.
Mandel J Dubois N Neuburger M Blanchard N 《Chemical communications (Cambridge, England)》2011,47(37):10284-10286
A conceptually novel approach to spiro- and dispiroketals of various ring-sizes under neutral conditions has been designed which complements the classical thermodynamically driven tactic. Key steps involved the formation of α-alkoxyfurans, their [4+2] or [4+3] cycloaddition reactions and the ring-rearrangement metathesis of the resulting oxabicycles. 相似文献
133.
Canioni R Marchal-Roch C Leclerc-Laronze N Haouas M Taulèlle F Marrot J Paul S Lamonier C Paul JF Loridant S Millet JM Cadot E 《Chemical communications (Cambridge, England)》2011,47(22):6413-6415
{Mo(132)} Keplerate anion reacts with tellurites to give a soluble precursor to produce in hydrothermal conditions single-phase M1 MoVTeO light-alkanes oxidation catalyst. Characterization of this Te-containing intermediate by single-crystal X-ray diffraction, (125)Te NMR, UV-visible and redox titration reveals a molybdotellurite anion as a crown-capped Keggin derivative. 相似文献
134.
135.
136.
The calculation of maximum transient energy growth is a problem of interest in several areas of science and engineering. An
algorithm that guarantees the calculation of this measure to an arbitrary accuracy in a finite number of steps is proposed
for finite-dimensional linear-time-invariant dynamical systems. The algorithm is illustrated with a numerical example. 相似文献
137.
Thomas Mouton Xavier Mercier Maxime Wartel Nathalie Lamoureux Pascale Desgroux 《Applied physics. B, Lasers and optics》2013,112(3):369-379
This paper presents the study we carried out on the formation of soot particles in low-pressure premixed CH4/O2/N2 flames by using Laser-Induced Incandescence (LII). Flames were stabilised at 26.6 kPa (200 torr). Four different equivalence ratios were tested (Φ = 1.95, 205, 2.15 and 2.32), Φ = 1.95 corresponding to the equivalence ratio for which LII signals begin to be measurable along the flame. The evolution of the LII signals with laser fluence (fluence curve), time (temporal decay) and emission wavelength is reported at different heights above the burner. We specifically took advantage of the low-pressure conditions to probe with a good spatial resolution the soot inception zone of the flames. Significant different behaviours of the fluence curves are observed according to the probed region of the flames and Φ. In addition, while the surface growth process is accompanied by an increase in the LII decay-times (indicator of the primary particle diameter) at higher Φ, decay-times become increasingly short at lower Φ reaching a constant value along the flame at Φ = 1.95. These behaviours are consistent with the detection of the smallest incandescent particles in the investigated flames, these particles having experienced very weak surface growth. Flame modelling including soot formation has been implemented in flames Φ = 2.05 and 2.32. Experimental quantitative soot volume fraction profiles were satisfactorily reproduced by adjusting the fraction of reactive soot surface available for reactions. The qualitative variation of the computed soot particle diameter and the relative weight of surface growth versus nucleation were consistent with the experimental observations. 相似文献
138.
Nathalie Deruelle Jean-Philippe Uzan 《International Journal of Theoretical Physics》1997,36(11):2461-2468
We briefly recall the problem of defining conserved quantities such as energy in general relativity, and the solution given
by introducing a symmetric background. We apply the general formalism to perturbed Robertson-Walker spacetimes with de Sitter
geometry as background. We relate the obtained conserved quantities to Traschen's integral constraints and mention a few applications
in cosmology. 相似文献
139.
Dissolved Cu(II) speciation in unpolluted soil solutions from different horizons was studied using differential pulse anodic stripping voltammetry (DPASV). Three sites were selected according to topography and monitored for three years. Experiments evidence Cu(II) can be bound by DOM (Dissolved Organic Matter) through complexation and/or adsorption reactions. The complexation capacity and the corresponding conditional stability constant were determined for complexation reactions. The adsorbing sites were titrated. A potential binding coefficient was calculated to compare both types of reactions. Results show adsorption is less frequent than complexation but exhibits higher binding coefficient. 相似文献
140.
Nicolas Cocherel Cyril Poriel Dr. Joëlle Rault‐Berthelot Dr. Frédéric Barrière Dr. Nathalie Audebrand Dr. Alexandra M. Z. Slawin Prof. Dr. Laurence Vignau Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2008,14(36):11328-11342
New routes to ladder‐type phenylene materials 1 and 2 are described. The oligomers 1 and 2 , which possess a “3π‐2spiro” architecture, have been synthesized by using extended diketone derivatives 3 and 10 as key intermediates. The physicochemical properties of the new blue‐light emitter 2 were studied in detail and compared with those of the less‐extended 1 . Owing to the recent development of fluorenone derivatives and their corresponding more conjugated analogues as potential electron‐transport materials in organic light‐emitting diodes (OLEDs) and as n‐type materials for photovoltaic applications, we also report herein the thermal, optical and electrochemical behavior of the key intermediates, diketones 3 and 10 . Finally, the application of dispiro 2 as a new light‐emitting material in OLEDs is reported. 相似文献